Europhys. Lett.
Volume 63, Number 5, September 2003
Page(s) 715 - 721
Section Electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics
Published online 01 November 2003
DOI: 10.1209/epl/i2003-00572-5
Europhys. Lett., 63 (5) , pp. 715-721 (2003)

Putting hydrodynamic interactions to work: Tagged-particle separation

J. L. Iguain1 and J. Kurchan2

1  Laboratoire de Physique Théorique et Hautes Energies, Jussieu, 5ème étage, Tour 24 Unité Mixte de Recherche CNRS UMR 7589 - 4 Place Jussieu, 75005 Paris, France
2  PMMH Ecole Supérieure de Physique et Chimie Industrielles Unité Mixte de Recherche CNRS UMR 7636 10 rue Vauquelin, 75231 Paris Cedex 05, France

(Received 24 January 2003; accepted in final form 18 June 2003)

Separation of magnetically tagged cells is performed by attaching markers to a subset of cells in suspension and applying fields to pull from them in a variety of ways. The magnetic force is proportional to the field gradient, and the hydrodynamic interactions play only a passive, adverse role. We propose using a homogeneous rotating magnetic field only to make tagged particles rotate, and then performing the actual separation by means of hydrodynamic interactions, which thus play an active role. The method, which we explore here theoretically and by means of numerical simulations, lends itself naturally to sorting on large scales.

47.85.-g - Applied fluid mechanics.
87.19.Tt - Rheology of body fluids.
83.80.Lz - Physiological materials (e.g. blood, collagen, etc.).

© EDP Sciences 2003